App Dev Worksheet: Events

App development lesson 17: Events: on tap, do this · Set 276 · 40 questions

Developer's tip (When this, do that): Event → handler → action: “on tap, do this”. The handler runs once for every tap. Counter: start + taps × step. A limit stops it growing; on = !on flips ON / OFF.

1. 1.True or false: the user taps Play is a text event. (a) True (b) False
2. 2.👆 What kind of event is this: a finger hits Like? (a) a timer event (b) a load event (c) a tap event (d) a text event
3. 3.👆 What kind of event is this: the app starts up? (a) a tap event (b) a timer event (c) a text event (d) a load event
4. 4.👆 The user taps the button 1 times. What number does the label show now?
   let likes = 0;
   button.onTap = function () {
     if (likes < 5) {
       likes = likes + 1;
     }
     label.text = likes;
   };
5. 5.👆 The user taps the button 6 times. What number does the label show now?
   let score = 1;
   button.onTap = function () {
     score = score + 3;
     label.text = score;
   };
6. 6.👆 The user taps the button 8 times. What number does the label show now?
   let likes = 0;
   button.onTap = function () {
     if (likes < 4) {
       likes = likes + 1;
     }
     label.text = likes;
   };
7. 7.👆 The user taps the button 3 times. What does the label show now?
   let on = false;
   button.onTap = function () {
     on = !on;
     if (on) {
       label.text = "ON";
     } else {
       label.text = "OFF";
     }
   }; (a) ON (b) OFF
8. 8.👆 The user taps the button 8 times. What number does the label show now?
   let likes = 0;
   button.onTap = function () {
     if (likes < 2) {
       likes = likes + 1;
     }
     label.text = likes;
   };
9. 9.👆 The user taps the button 2 times. What number does the label show now?
   let likes = 0;
   button.onTap = function () {
     if (likes < 5) {
       likes = likes + 1;
     }
     label.text = likes;
   };
10. 10.👆 The user taps the button 5 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 3) {
        likes = likes + 1;
      }
      label.text = likes;
    };
11. 11.👆 The user types Aman in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hi, " + nameBox.text + "!";
    }; (a) Hi! (b) Hi, nameBox.text! (c) Hi, Aman! (d) Aman
12. 12.👆 The user taps the button 6 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 1;
      label.text = points;
    };
13. 13.👆 An event in an app is ___. (a) a colour theme (b) something that happens (c) an app store (d) a kind of list
14. 14.True or false: the user taps Play is a load event. (a) True (b) False
15. 15.👆 The user taps the button 5 times. What number does the label show now?
    let points = 1;
    button.onTap = function () {
      points = points + 5;
      label.text = points;
    };
16. 16.👆 The user taps the button 7 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
17. 17.👆 The user taps the button 4 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    }; (a) OFF (b) ON
18. 18.👆 “On tap → do this” links an event to ___. (a) a web address (b) a font (c) an action (d) a charger
19. 19.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 3;
    button.onTap = function () {
      coins = coins + 4;
      label.text = coins;
    };
20. 20.👆 The user taps the button 3 times. What number does the label show now?
    let points = 6;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
21. 21.👆 The user taps the button 2 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
22. 22.👆 The user types Aman in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    }; (a) Hello, nameBox.text! (b) Hello, Aman! (c) Aman (d) Hello!
23. 23.👆 The user taps the button 6 times. What number does the label show now?
    let points = 0;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
24. 24.👆 The user taps the button 3 times. What number does the label show now?
    let coins = 5;
    button.onTap = function () {
      coins = coins + 3;
      label.text = coins;
    };
25. 25.👆 The user taps the button 2 times. What number does the label show now?
    let lives = 1;
    button.onTap = function () {
      lives = lives + 4;
      label.text = lives;
    };
26. 26.👆 What kind of event is this: the user types a letter? (a) a tap event (b) a timer event (c) a text event (d) a load event
27. 27.👆 The user taps the button 6 times. What number does the label show now?
    let lives = 7;
    button.onTap = function () {
      lives = lives + 5;
      label.text = lives;
    };
28. 28.👆 The user taps the button 3 times. What number does the label show now?
    let points = 5;
    button.onTap = function () {
      points = points + 3;
      label.text = points;
    };
29. 29.👆 What kind of event is this: a 5-minute alarm ends? (a) a timer event (b) a load event (c) a text event (d) a tap event
30. 30.👆 The user taps the button 5 times. What number does the label show now?
    let lives = 9;
    button.onTap = function () {
      lives = lives + 2;
      label.text = lives;
    };
31. 31.👆 Code that runs when an event happens is called a ___. (a) header (b) headline (c) hashtag (d) handler
32. 32.👆 The user types Riya in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Hello, " + nameBox.text + "!";
    }; (a) Riya (b) Hello, Riya! (c) Hello! (d) Hello, nameBox.text!
33. 33.👆 Which of these is an event? (a) the user taps a button (b) a list of names (c) the icon colour (d) the font size
34. 34.👆 The user types Arjun in nameBox and taps the button 1 time. What does the label show?
    button.onTap = function () {
      label.text = "Welcome, " + nameBox.text + "!";
    }; (a) Welcome! (b) Welcome, nameBox.text! (c) Arjun (d) Welcome, Arjun!
35. 35.👆 The user taps the button 5 times. What number does the label show now?
    let coins = 0;
    button.onTap = function () {
      coins = coins + 1;
      label.text = coins;
    };
36. 36.👆 The user taps the button 3 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 2) {
        likes = likes + 1;
      }
      label.text = likes;
    };
37. 37.👆 The user taps the button 7 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    }; (a) OFF (b) ON
38. 38.👆 The user taps the button 5 times. What number does the label show now?
    let likes = 0;
    button.onTap = function () {
      if (likes < 5) {
        likes = likes + 1;
      }
      label.text = likes;
    };
39. 39.👆 The user taps the button 2 times. What does the label show now?
    let on = false;
    button.onTap = function () {
      on = !on;
      if (on) {
        label.text = "ON";
      } else {
        label.text = "OFF";
      }
    }; (a) OFF (b) ON
40. 40.True or false: a countdown hits zero is a timer event. (a) True (b) False

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